Propulsion unit



. Nov. 28, 1939. J, c' w 2,181,244

PROPULSION UNIT I Original Filed May 16, 1955 3 Sheets-Sheet 1 NOV. 28, 1939. J A 'McGREw 2,181,244

PROPULSION UNIT Original Filed May 16, 1935 I5 Sheets-Sheet 2 v J? 3 1i Nov. 28, 1939. J, A McGRg-w 2,181,244

PROPULSION UNIT Original Filed May 16, 1935 5 Sheets-Sheet 3 23 Z6 Z6 x5 Patented Nov. 28, 1939 Original application May 16, 1935, Serial No.

21,855, now Patent No; 2,078,262, dated April Divided and this application December 4, 1936, Serial No. 114,240

5 Claims. (Cl. M -576) 'lhe present invention relates to propulsion units and particularly to propulsion units of the steam energized type and adapted for use on rail- I filed May 16, 1935, which has now matured as Patent No. 2,078,262, granted April 2'7; 1937, of. which the present application is a division, is disclosed and claimed a locomotive comprising a plurality of relatively small-compact individual propulsion units, each such unit being associated with a single driven axle. The arrangement is such that steam may be supplied to one, or a plurality, or all of these units depending upon the loads imposed upon the locomotive and the speed at which it is to be driven. Each unit embodies a steam actuated motor of reversible type and means for operatively connecting the motor to, and disconnecting it from, the associated axle, it being desired that one or more of the motors be disconnected from the axles with which they are associated when not supplied with steam, thereby greatly decreasing frictional losses. during the operation of the locomotive and minimizing wear of the several individual propulsion units. The present invention contemplates particularly details of construction of the individual propulsion units, particularly the organization of elements whereby the ready connection of the motor andaxle is ef-. fected when the motor is initially energized, and. disconnection brought about when the. motor is deenergized, this connecting and disconnecting means being operative for either direction of movement of the crank shaft, and the motor, the

motor being reversible.

It will be understood that in. a propulsion unit designed and intended for use as one of a plurality of similar units of a locomotive, ruggedness and compactness of construction are primary consid.-

erations. It isan object of the presentinvention toprovide a unit of the general type described in which the several parts are of simple nature while rugged and durable in use and which parts occupy such relationships to each other when as: sembled that the propulsion unit as a whole 00:- cupiesbut small space and hence may be readily assembled, together with a number of other units, beneath a locomotive boiler, without causing; the overall height of the locomotive to be excessive.

In the several figures of the drawings one embodiment of the invention is illustrated in detail, by way of example, and will now be described,

In the drawings:

Figure 1 shows in plan one of the improvedrqnu ohuh ts abortion f h QQRQI-QQY I Y site side ofthe. driven axle .H from. the cylinders casing being broken away and disclosing in plan a number of the operating parts; 3

Figure 2 is a section online 2,-2 of Figure l; Figure 3 is a section on line 3-3 of Figure 1;

- Figure 4,-is a section on line '4-4 of Figure 3;

Figured is a side elevation of a portion of the gearing of the propulsion unit, upon a somewhat larger-- scale; 2 r I Figures 6 and 7- are detailed views illustrating certain parts of the connecting means whereby 10 the motor may be connected to or disconnected from the axle to be driven.

The drawings do. not show all details of the propulsion unit, only such elements thereof as are necessary to a full understanding of the pres- 5 ent invention being, illustrated. For a full and complete understanding of all details of the unit reference may be had to my patent, previously referred to.

In Figure 1, which is a plan view of the unit, partly brokenaway, the unit is seen to comprise a frameor casing which is generally indicated by the numeral [0, and which frame or casing is mainly supported upon an axle. H to be driven, a bracket- 1 latone endofthe casing, however, be- 25 ing adapted to. be connected to. a truck frame member carried in part. by axle H, and. in part by one. or more additional. axles, in order to pre-- vent any substantial movement of rotation of the frame I0 about the axisof'the axle l;|.. Cylinders of the motor carried by the frame 10' are positioned-r at one end of the frame, being indicated at 13. and a crank shaft to, be drivenby the motor is indicated at 1:41, being positioned upon theoppoand being-operatively connected to the pistons mounted for, recipr c iohz e cy i der by h usual piston rod, cr ss. head and ink. nstru tion, which it is, not. necessary to, describe. Eachcylinder. is; equipped. with. Su ta e va v mechan smi Q i contro n the 19 te m-wa d fr mthe. same, cheer the valves ein d a d at. 5, E si re and h s val being a t from crank shaft by avalveoperating mechanism, generally indicated at M, which includes means for; reversing the motor. So far as the present invention is concerned this valvereversing mechanism may be varied, design and dea ls o c ns ruc n,

F xed up r n a t o f rmin n in- 50 tegral Part thereof, is a driving pinion 1 6 the teeth-of which are in constant mesh with those of amm hr fl dr n se I1 m d. fa tation about; the axis of axle Gear H is in the s h ra iorm otahql a hyl h enas l rly 55,

the gear as by means of bolts 2| and having their inner flanged margins rotatably supported upon the axle through the intermediate annular bearing members 22 of angular cross-section, each such bearing member having a cylindrical portion bearing against the cylindrical outer face of the axle and also an annular face bearing against.

the adjacent annular face of sleeve l8 fixed to the axle, gear I! being thus supported for free rotation upon the axle and being maintained against sliding movement longitudinally of the axle by reason of the interengagement of sleeve 18 and annular bearing members 22.

Intermediatethe inner face of gear IT and the outer face of sleeve it are positioned two sets of swinging pawls, one set of these pawls being indicated by the numerals 24 and the other set by the numerals 25, the pawls of one set being similar to the pawls of the other set but oppositely directed. Each pawl is adapted to swing angularly about an axis fixed with respect to gear I! and to rest at all times against an abutment surface rigid and movable with gear H. Thus the gear is shown to be provided with a plurality of abutments 26, projecting radially inwardly toward sleeve 18, each such abutment being provided with two cylindrical pawl seats, indicated at 26' and 26 respectively, the first being for one of the pawls 24 and the second for one of the pawls 25. Each pawl is adapted to swing about an axis closely adjacent its seat and to be moved by such swinging motion either into position to engage one or another of the outwardly projecting abutments or teeth 28 of sleeve I8, or outwardly into a recess formed in gear H for its reception. In Figure 4 of the drawings the several pawls 24 are shown to be swung inwardly so that their free ends operatively engage, respectively, certain teeth of sleeve I8, and the pawls 25 are shown in. their outward or inoperative positions, a driving connection being therefore established between the gear I! and axle H, through sleeve 18, in the event that gear [1 is rotated by pinion H in a counter-clockwise direction. When the motor is reversed, the driving connection between gear I! and sleeve I8 is brought about by retraction of pawls 24 and inward movement of the set of pawls 25 so that it is by means of the operation of the two sets of pawls, alternatively, as just described, that an effective driving connection between the gear I! and axle Il may be established, regardless of the direction of operation of the motor.

In the normal operation of the propulsion unit the positions of the pawls are changed automatically when reversal of motion of gear I! is effected by reversal of drive of the motor, and when the motor is deenergized while the axle is rotating, both sets of pawls are caused to occupy their inoperative positions. The means for causing the pawls to thus automatically operate will now be described. Each pawl is provided at the ends thereof with trunnions coaxial with the axis of rotation of the pawl when swinging upon jecting inwardly toward the axle.

its seating surface, trunnions 30 and 3| of one of the pawls 25 being illustrated in Figure 3. Trunnion 30 fits closely Within a cylindrical aperture formed in the adjacent side plate 26 and. trunnion 3| projects through a slot 33, formed in the opposite side plate 20, being seated for rotation in the curved outer end of such slot, which functions as a bearing for the trunnion. Integral with trunnion 3| is a trunnion arm 34 pro- The end of trunnion arm 34 is rounded and lies between spaced lugs 35 which comprise integral portions of an annular ring 36 rotatably mounted upon a bearing sleeve 37 retained within and forming a part of bearing assembly 38 which comprises one of the main supporting bearings whereby the weight of the frame, motor and other parts, are transmitted to the axle. Engaging the outer cylindrical surface of ring 36 are segmental friction shoes 39, each pivotally mounted at its lower end upon a pin 40 supported in the cap of bearing 38 and the upper ends of shoes 39 being resiliently drawn together at all times by spring means such as clearly illustrated in Figure 2. Thus the adjacent ends of shoes 39 are provided with upwardly extending portions 39' positioned in close proximity to each other and these portions 39 are provided with aligned cylindrical apertures through which the horizontally disposed rod 4| extends.

Encircling rod 4! are the coiled compression springs 42, each spring hearing at one end upon the associated friction shoe projection 39' and upon the other end against a collar or washer 43, which in turn rests against a nut 44 having threaded engagement with rod 4!. By adjusting nuts 44, the tension of springs 42 may be increased or decreased as desired and hence the adjacent ends of friction shoes 39 urged more or less strongly toward each other and against ring 36. By adjusting this spring mechanism, therefore, the degree of frictional opposition to rotation to ring 36 may be varied. In any event, ring 36 will oppose revolution of the inner end of trunnion arm 34, when gear I! is initially rotated about axle H and will, when the gear is rotated in one direction, tend to move the associated pawl into operative position, and when rotated in the opposite direction, will tend to move the associated pawl into inoperative position. It will be appreciated that two of the annular rings and frictional retarding mechanism are provided, one upon each side of gear II, as clearly shown in Figure 3, and that the trunnion arms 34 of one set of pawls will be operatively connected to one of these rings 36 and the trunnion arms of the second set of pawls to the second ring 36. The efiect of this arrangement of course is to cause one set of pawls to move into position to engage the teeth 28 of sleeve l8 when gear I! is moved in one direction, the second set of pawls being simultaneously moved to inoperative position, the movements of the pawls being reversed when the direction of rotation of gear ll about the axle is reversed, so that an operative connection between gear I! and axle H is established regardless of the direction of drive of the motor.

Itis essential, of course, that the means just described for establishing the driving connection between motor and axle, regardless of the direction of drive of the motor, shall not interfere with the free rotation of the axle when the motor is not in operation. The construction just described is such that the set of pawls which may be functioning to establish the driving connection between gear H and the axle at the time of deenergization of the motor will be automatically and instantly'removed to inoperative position. Thus in Figure 4 of the drawings the several pawls 24 are shown in engaged position, disposed,

respectively, substantially tangentially to the outer face of sleeve [8 and the free ends of the pawls being in'contact with teeth 28 projecting from this sleeve. Counter-clockwise rotation of gear .51 is communicated to the sleeve I8 by means of these pawls 2 Should the locomotive with which the propulsion unit is used be in motion when the motor'is deenergized, gear I! will of course cease to rotate while the axle II and sleeve is will continue to rotate in a counterclockwise direction. Hence the inner surfaces of the several pawls 24 will be immediately engaged by the still revolving teeth 28 of sleeve l8 and will be thrust outwardly into the several recesses provided for their reception, by the action of these teeth, the inner faces of the pawls being provided with longitudinally extending raised portions 2 1 which in reality comprise cam portions coacting with the teeth 28. After effecting complete displacement of pawls 24 from the paths of the revolving teeth 28, pawls 24 will be firmly retained intheir outer or inoperative positions by the action of the annular ring 36 to which they are operatively connected, this ring, being frictionally held in fixed position upon its supporting sleeve by the action of the friction shoes 39, as soon as the outward swinging motion of pawls 24 under the action of teeth 28 have ceased.

Both sets of pawls are of course similarly moved into, and held, in inoperative positions,

pawls 25 being provided with similar cam. surfaces 25' for coaction with teeth 28 of sleeve I8.

It is clear therefore that the foregoing arrangement provides a most compact as well as a 'rugged, durable, and automatically operating a gear encircling the axle, rotatable thereon and always adapted to be driven in either direction; the combination of opposed sets of rocking pawls disposed intermediate said gear and axle and trunnioned in said gear, one set for operatively connecting the gear and axle when the gear is rotated in one direction and the second set acting to connect the gear and axle when the gear is rotated in the reverse direction, cam portions formed on said pawls and adapted to be engaged operatively connected with and relatively movable with respect to the other set of pawls to rock them into engagement with the axle when the gear is rotated in the reverse direction.

2, In a propulsion unit for use on railroads or the like, which includes an axle to be driven, and

a gear encircling the axle, rotatable thereon, and

alwaysadapted to be driven in either direction; the combination of opposed sets of rocking pawls disposed intermediate said gear and axle and trunnioned in said gear, one set of pawls for operatively connecting the gear-and axle when the gear isrotated in one direction and the other set acting to connect the gear and axle when the gear is rotated in the reverse direction, a frictionally retarded element positioned upon one side of, said gear and operatively connected with one set of pawls to rock them into engagement with said axle when said gear is rotated in one direction, another frictionally retarded element positioned upon the opposite side of said gear and operatively connected with the other set of pawls to rock them into engagement. with the axle when the gear is rotated in the reverse direction, and oppositely extending crank arms on the pawls of. said respective sets and operatively connected with said frictionally retarded elements. I

3. In a locomotive propulsion unit or the like, which includes a driving axle member and a gear member rotatably mounted thereon; the com bination of pawls rockably trunnioned in one of said members and movable into and out of engagement with the second member, means operatively connected with said pawls for effecting their engagement when relative rotation of said members in one direction occurs and for disengaging the pawls when said members relatively rotate in the opposite direction, said means including an annular ring supported upon a stationary portion of said unit concentric with the axle, and an adjustable spring pressed braking element for engaging said ring to restrict rotary movement thereof in either direction.

4. In a propulsion unit, which includes an axle to be driven, and a gear member encircling the axle, rotatable thereon and adapted to be driven in either direction; the combination of opposed sets of rocking pawls positioned intermediate said gear and axle, each of said pawls'being provided with oppositely directed trunnions pivotally mounted in said gear member, one set of pawls for operatively connecting the gear member and axle when the gear member is rotated in one direction and the second set acting to connect the gear member and axle when the gear member is rotated in the reverse direction, a frictionally retarded element positioned upon one side of said gear member and operatively connected with and relatively movable with respect to one set of. pawls to rock them into engagement with said axle when said gear member is rotated inone direction, and another frictionally retarded element positioned upon the opposite side of said gear member and operatively connected with and relativelymovable with respect to the other set of pawls to rock them into engagement with the axle when the gear member is rotated in the reverse direction.

5. In a propulsion unit, which includes an axle to be driven, and a gear encircling the axle, rotatable thereon, and adapted to be driven in either direction; the combination of opposed sets of rocking pawls disposed intermediate said gear and axle and trunnioned in said gear, one set of and the other set acting to connect the gear and axle when the gear is rotated in the reverse direction, a frictionally retarded element positioned upon one side of said gear and operatively connected with one set of paWls to rock them into engagement with said axle when said gear is rotated in one direction, another frictionally retarded element positioned upon the opposite side of said gear and operatively connected with the other set of pawls to rock them into engagement with the axle when the gear is rotated in the reverse direction, each frictionally retarded element comprising an annular ring rotatably supported upon a stationary portion of said unit concentric with said axle, the means for retarding said elements comprising adjustable spring-pressed brake shoes bearing upon a portion of the periphery of. each ring, and oppositely extending crank arms on the pawls of said respective sets and operatively connected with said frictionally retarded elements. 7

JOHN A. MCGREW. 

